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#! /usr/bin/python2
#
# Copyright 2016 the V8 project authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
#
import argparse
import collections
import re
import subprocess
import sys
__DESCRIPTION = """
Processes a perf.data sample file and reports the hottest Ignition bytecodes,
or write an input file for flamegraph.pl.
"""
__HELP_EPILOGUE = """
examples:
# Get a flamegraph for Ignition bytecode handlers on Octane benchmark,
# without considering the time spent compiling JS code, entry trampoline
# samples and other non-Ignition samples.
#
$ tools/run-perf.sh out/x64.release/d8 \\
--ignition --noturbo --nocrankshaft run.js
$ tools/ignition/linux_perf_report.py --flamegraph -o out.collapsed
$ flamegraph.pl --colors js out.collapsed > out.svg
# Same as above, but show all samples, including time spent compiling JS code,
# entry trampoline samples and other samples.
$ # ...
$ tools/ignition/linux_perf_report.py \\
--flamegraph --show-all -o out.collapsed
$ # ...
# Same as above, but show full function signatures in the flamegraph.
$ # ...
$ tools/ignition/linux_perf_report.py \\
--flamegraph --show-full-signatures -o out.collapsed
$ # ...
# See the hottest bytecodes on Octane benchmark, by number of samples.
#
$ tools/run-perf.sh out/x64.release/d8 \\
--ignition --noturbo --nocrankshaft octane/run.js
$ tools/ignition/linux_perf_report.py
"""
COMPILER_SYMBOLS_RE = re.compile(
r"v8::internal::(?:\(anonymous namespace\)::)?Compile|v8::internal::Parser")
def strip_function_parameters(symbol):
if symbol[-1] != ')': return symbol
pos = 1
parenthesis_count = 0
for c in reversed(symbol):
if c == ')':
parenthesis_count += 1
elif c == '(':
parenthesis_count -= 1
if parenthesis_count == 0:
break
else:
pos += 1
return symbol[:-pos]
def collapsed_callchains_generator(perf_stream, show_all=False,
show_full_signatures=False):
current_chain = []
skip_until_end_of_chain = False
compiler_symbol_in_chain = False
for line in perf_stream:
# Lines starting with a "#" are comments, skip them.
if line[0] == "#":
continue
line = line.strip()
# Empty line signals the end of the callchain.
if not line:
if not skip_until_end_of_chain and current_chain and show_all:
current_chain.append("[other]")
yield current_chain
# Reset parser status.
current_chain = []
skip_until_end_of_chain = False
compiler_symbol_in_chain = False
continue
if skip_until_end_of_chain:
continue
# Trim the leading address and the trailing +offset, if present.
symbol = line.split(" ", 1)[1].split("+", 1)[0]
if not show_full_signatures:
symbol = strip_function_parameters(symbol)
current_chain.append(symbol)
if symbol.startswith("BytecodeHandler:"):
yield current_chain
skip_until_end_of_chain = True
elif symbol == "Stub:CEntryStub" and compiler_symbol_in_chain:
if show_all:
current_chain[-1] = "[compiler]"
yield current_chain
skip_until_end_of_chain = True
elif COMPILER_SYMBOLS_RE.match(symbol):
compiler_symbol_in_chain = True
elif symbol == "Builtin:InterpreterEntryTrampoline":
if len(current_chain) == 1:
yield ["[entry trampoline]"]
else:
# If we see an InterpreterEntryTrampoline which is not at the top of the
# chain and doesn't have a BytecodeHandler above it, then we have
# skipped the top BytecodeHandler due to the top-level stub not building
# a frame. File the chain in the [misattributed] bucket.
current_chain[-1] = "[misattributed]"
yield current_chain
skip_until_end_of_chain = True
def calculate_samples_count_per_callchain(callchains):
chain_counters = collections.defaultdict(int)
for callchain in callchains:
key = ";".join(reversed(callchain))
chain_counters[key] += 1
return chain_counters.items()
def calculate_samples_count_per_handler(callchains):
def strip_handler_prefix_if_any(handler):
return handler if handler[0] == "[" else handler.split(":", 1)[1]
handler_counters = collections.defaultdict(int)
for callchain in callchains:
handler = strip_handler_prefix_if_any(callchain[-1])
handler_counters[handler] += 1
return handler_counters.items()
def write_flamegraph_input_file(output_stream, callchains):
for callchain, count in calculate_samples_count_per_callchain(callchains):
output_stream.write("{}; {}\n".format(callchain, count))
def write_handlers_report(output_stream, callchains):
handler_counters = calculate_samples_count_per_handler(callchains)
samples_num = sum(counter for _, counter in handler_counters)
# Sort by decreasing number of samples
handler_counters.sort(key=lambda entry: entry[1], reverse=True)
for bytecode_name, count in handler_counters:
output_stream.write(
"{}\t{}\t{:.3f}%\n".format(bytecode_name, count,
100. * count / samples_num))
def parse_command_line():
command_line_parser = argparse.ArgumentParser(
formatter_class=argparse.RawDescriptionHelpFormatter,
description=__DESCRIPTION,
epilog=__HELP_EPILOGUE)
command_line_parser.add_argument(
"perf_filename",
help="perf sample file to process (default: perf.data)",
nargs="?",
default="perf.data",
metavar="<perf filename>"
)
command_line_parser.add_argument(
"--flamegraph", "-f",
help="output an input file for flamegraph.pl, not a report",
action="store_true",
dest="output_flamegraph"
)
command_line_parser.add_argument(
"--show-all", "-a",
help="show samples outside Ignition bytecode handlers",
action="store_true"
)
command_line_parser.add_argument(
"--show-full-signatures", "-s",
help="show full signatures instead of function names",
action="store_true"
)
command_line_parser.add_argument(
"--output", "-o",
help="output file name (stdout if omitted)",
type=argparse.FileType('wt'),
default=sys.stdout,
metavar="<output filename>",
dest="output_stream"
)
return command_line_parser.parse_args()
def main():
program_options = parse_command_line()
perf = subprocess.Popen(["perf", "script", "--fields", "ip,sym",
"-i", program_options.perf_filename],
stdout=subprocess.PIPE)
callchains = collapsed_callchains_generator(
perf.stdout, program_options.show_all,
program_options.show_full_signatures)
if program_options.output_flamegraph:
write_flamegraph_input_file(program_options.output_stream, callchains)
else:
write_handlers_report(program_options.output_stream, callchains)
if __name__ == "__main__":
main()
|
